In prior submerged arc bulkwelding, for example as disclosed in my U.S. Pat. Nos. 3,076,888, 3,060,307, and 3,172,991, it has been necessary to feed the weld powder or particles into the weld zone on the work first, followed by the flux covering and the electrode. This requires sequential starts and stops in that in starting the powder feed must first be activated, then the travel started, then the flux feed activated and then the wire or electrode feed activated, and at the finish, the respective feeds and travel are deactivated in the reverse order. This results in inconvenience, and since the travel distance of the equipment because of the procedures is several inches longer, results in loss of time and materials and it requires skill in starting and stopping.
These difficulties are eliminated by the present invention wherein the electrically conductive, consummable electrode and flux are fed together as in an ordinary sub-arc operation but magnetically-responsive weld powder or particles are fed to the wire which magnetically adheres to it and are fed down through the flux into the weld zone. There is thus no need for sequential starts and stops and eliminates problems in connection therewith, and the whole welding operation operates from one start and stop switch.
The procedure of feeding materials into a weld zone by magnetic means is not new as fluxing material of some magnetic capacity has been fed in this manner. However, primary welding materials which are fully magnetically-responsive materials, such as iron powder, have not been fed in this way because the feeder nozzle jams and stops the flow of the powder or particles. The prior nozzles which are used were always metallic or had a metallic jacket. It was discovered that fluctuation in the current flowing in the electrode induced an electric current in the nozzle which set up a magnetic field around the nozzle which magnetically attracted the magnetically-responsive weld particles and caused this plugging and stoppage. The apparatus of the present invention by which methods of the present invention can be practiced includes a feeder having a nozzle which is formed of an electrically non-conducting material, such as a ceramic material, so that a magnetic field is not set up around and accordingly the nozzle does not magnetically attract the magnetically-responsive weld particles and clog, and the weld powder or particles magnetically adhere so tightly to the electrode that they are fed down through the flux into the weld zone, thus producing a viable and much more simplified welding procedure.